Monthly Archives: February 2018

13 posts

President’s Corner for Feb/Mar 2018

Hey Team,

I hope everyone enjoyed our tropical February as much as I did! Every once in a while I need to be reminded why I put up with high taxes, the most expensive gasoline in the country, and of course- those Crazy Californians! Not as much rain as last year, and I am not sure that is a good thing or not… There has not been a growth explosion in the outer area yet, and that is good for the allergy sufferers, but we need a better dousing to keep our runway well packed. If it doesn’t come, Jim will be renting the water truck again and an even larger steam roller in an attempt to keep the runway from chunking up before summer.

We keep having issues with the gate and unauthorized use of our site. PLEASE close the gate if you are the last one out! Again there have been reports of members arriving in the afternoon to an open gate and non-members on site flying over Sea world drive and the marsh refuge area. Kind of hard to argue our case to the City that it’s not us if they are seen STANDING ON OUR SITE while doing stupid stuff…  Close the gate.

We had a pretty neat event at the FPV rotorplex last weekend. Club members had a fun race put together by “the Bomb Squad . A few non-members (with AMA) showed up and were able to join in for a small fee. On the plus side, a few of the non-members subsequently joined the club – Welcome! On the negative side (there is always one poison pill) one of the non-members crashed all of his drones, vandalized a member’s vehicle in our lot, and then proceeded to tear through our site at over well 50 MPH. We couldn’t file a report as all we had was his first name… I think we need to put more thought into future “open” events.

Not too much excitement or blood in the pits this month – is Skip doing ok? But I would like everyone to take a look at their first aid kits to ensure the contents are still usable. We had to super glue Randy’s finger shut last month because his (and mine) band aids wouldn’t stick after spending the year in our hot vehicles.

 There was a surprising amount of unsafe flying witnessed this month. There were at least 6 incidents when planes were over my head in the pits, and I only see the weekend stuff. One plane slammed into the pits a few feet away from a young couple with small children that were spectating in the pit area. NO flying over the pits or over the fence line– EVER! The runway and airspace over the runway is for taking off and landing ONLY. Once airborne, clear the runway.

  I would like to lay down a reminder that ALL members are empowered to ensure the safe and responsible use of our site. You DO NOT have to wait for a board member to say something if you see irresponsible use of our facility. If there in an incident involving the public at large, WE stand to lose OUR site, not just the 9 members of the board.

Finally, We need to keep up the press for people to quit messing around with membership and join the club. We are around 75% on renewals, which is not bad – but behind where we were last year. There is no value in holding off, it will be the same $50 all year. Please display your 2018 badges at all time or be prepared to be approached. Remarkably, the ones that always overfly the pit area also seem to be the ones without a 2018 badge – coincidence?  Let’s try some peer pressure, up to telling them they cannot fly without membership. Why should they enjoy for free the club benefits you have paid for?

This month’s fun fly event on the 24th will be spot landing. Another favorite that anyone can play. Sorry, no “ Micro” aircraft  on this one. The event will kick off at 10:00 AM, followed by the monthly club meeting at the field, and a hot dog lunch.

Fly safe!


Electroglide Report for February 2018

By Jeff Struthers

We had a fun Electroglide last Saturday. I don’t think we could have had a better San Diego day. Lindbergh field’s 10:00 a.m. report shows 67 degrees, calm winds, partly cloudy skies with 10-mile visibility.

Eight pilots showed up, one Easy Star, one open class and six Radians took to the sky a little after 10:00.

First launch had us all looking for the lift. Flight times were modest. Dennis La Bergh had the long flight of 8:30, the rest of us were coming down in the mid 4 minutes. Jim Bonnardel and Electroglide newcomer Carlos Mercado both had 20-point landings, Jon Graber had a 10-point landing.

Second launch had conditions changing, a lot! Flight times jumped with five pilots flying beyond 8 minutes. Jim Bonnardel flew the longest for a 9:55 aloft. Roger Ball had a 9:46 and Scott Vance had 9:23 aloft. I got lucky with a 30-point landing. Scott had a 20-point with Jim, Roger and Carlos all getting 10-point landings.

Third launch again yielded some long flights. I had a flight of 9:43 and Roger Ball came in two seconds after me at 9:41. Tom Erickson coming back to the field at 9:17. Tom, Dennis and myself picked up 20-point landings. Jim, Roger and Scott Vance scored 10-point landings. Some good lift on the second and third launches.

The NW wind was picking up for the forth and final launch and made finding the lift a harder thing to do. Scott found some ridge lift near the palm trees in our NW flying area, gently working out the long flight of 8:28. Jim had an 8:02 flight and Dennis had a flight of 8:00. Jim, Scott, Dennis and myself picked up 20-point landings.

Top score for the day was Jim Bonnardel flying in the open class with 250 points. I was flying a Radian and got lucky with my extra point landings bringing me in second at 247 points. Scott Vance came in third at 237 points. Dennis LaBerge was fourth at 227 points. Both flying with Radians.

It was a great day to fly gliders in San Diego. Sunshine, Blue skies, high scattered clouds and thermals. The 10:00 start time is working out well, so we’ll do it again next month on March 17th.

See you then,


Dennis coming back

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Prism Zero G RC Kite at SEFSD

By Rob Jahnke

I live in Minnesota but spend January in San Diego. I enjoy flying with the Silent Electric Flyers of San Diego (SEFSD) at the Mission Bay field, but I needed a reasonably sized model airplane that would travel well on an airline. I modified a Prism Zero G Glider kite (purchased at the kite store in Seaport Village) for this mission. As a kite, it flies in the Canard configuration. As an airplane,  I put the motor on the opposite end and use the canard surfaces as elevators. A light weight rudder was added for the airplane configuration.

The conversion was very successful. The video shows test flights at the Coronado Tidelands Park flying both as an airplane and a kite. In smooth air, it flies “hands off”.

YouTube video – 1 min 12 sec  Coronado test flight:

The Wingspan is 1067 mm (42″) and the “All Up Weight” is 225 grams (8 oz) including a 1.3 gram recording altimeter. Flight time is 15 minutes with a 3S 500 mah LiPo and a 9 x 4.7 prop. At the SEFSD field, I recorded a maximum altitude of 352 ft. The only real concern with this model airplane is that you could easily lose it in a thermal. So morning, or evening, or cloudy days are best. It also flies well in a gymnasium.

YouTube video – 1 min 28 sec   College of St. Benedict Field House:

Since we stay in Coronado for the month of January, the Zero G RC Kite makes a great backpack airplane. I ride the Coronado Ferry to the Broadway Pier, then take the trolley to the Morena/Linda Vista stop. The bike takes me the rest of the way to the SEFSD field.

Rob Jahnke

Member – SEFSD (San Diego CA), MARCS (Madison WI),  Northstar Flyers (Holdingford MN) 

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BOD Minutes for Feb 2018

SEFSD BOD Meeting by Ken Dresser

Call to order 720 pm

Brad, Randy, Quan, Ken, Carl, Tony, Jim & Dennis

Verify membership app is up and running.

Helicopters are flying at landing pattern. Need a solution.

272 paid members so far, ..will email to non paid members and ask for keys back ..

Feb 24 club meeting and spot landing

March 24 jet day

April 15 photo day

Feb 17 FPV Race day 5 dollars for non club members, AMA required.

Please close the gate last one out

Friday March 9 BOD meeting.

Ken proposes Sunset/Night flying every first Saturday of the month.

Meeting adjourned at 8:34 pm

Reading and Understanding LiPo Labels and Specifications

Based on a Presentation by Ken Myers to the Midwest RC Society in Feb. 2018

The Label:
   The G5, at the top left of the label, indicates that it is a 5th Generation Hyperion brand LiPo battery. The SV, at the upper left and right indicate that it is a Standard Voltage type.
   There are High Voltage (HV) LiPo batteries, with a charge termination voltage of 4.35V/cell.
   The 4.20V/Cell Max Charge, under the SV on the right side of the label, indicates that it is to be charged to a termination voltage of 4.20V per cell. Again, this indicates that this is a SV LiPo and not a HV LiPo.
   The 3S/11.1V indicates that the battery is 3 cells connected in series (S) and that it has a nominal voltage of 11.1V. The 11.1 is not a cardinal number, it is a nominal number, a number that names something. It has no useful numeric value. Each SV LiPo cell is said to have a nominal (naming) value of 3.7V per cell, therefore, three cells in series is the sum of three nominal 3.7V cells.
   All that the notation of 3S/11.1V is doing is confirming that this is a 3 cell in series SV LiPo battery.
   It should be noted that some chargers also display a similar notation on a ‘confirmation’ screen before the charger can be started by the user when balance charging.
   50C Maximum states the manufacturer’s maximum recommended discharge rate.
   2100mAh is the manufacturer’s stated capacity.

A Comment Before A Closer Look at the Specifications

   For almost all of our electrically powered flight systems, we measure the current in amps (A), not milliamps (mA). That becomes relevant when discussing capacity, charge rates and discharge rates.

Breaking Down the Specification Numbers

   The following specifications were cut and pasted directly from the supplier’s Web site for this battery.

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Hyperion G5 50C Max – 2100mah 3S Lipo
Capacity: 2100mah
Voltage: 3S, 11.1v nominal
Discharge Rate: 50Cmax (50C burst, 25~30C continuous)
Charge Rate: 6C maximum, 5C recommended
Weight: 163 grams
Dimensions: 105 x 34.1 x 21.7mm
Power Connector: XT-60
Balance Connector: JST-XH
CMax = Continuous C-Rate for 100% rated capacity delivery is 1/2 C-Max rate.

* * * * *

Hyperion G5 50C Max – 2100mah 3S Lipo
Capacity: 2100mah (should be mAh)
   The manufacturer’s stated battery capacity is based on a constant current load that they say is required to take a cell/battery from ‘full volts (V)’ to ’empty volts (V)’ in one hour.

   What is the ‘Full’ and ‘Empty’ voltage?
   Full voltage for a Standard Voltage LiPo cell is usually stated as 4.20V per cell, as noted on the label. Therefore, a pack with 3 cells in series (3S) has a stated voltage 3 times 4.20V. That is 12.60V for the 3S example pack.
   Empty voltage for a Standard Voltage LiPo cell is usually given as 3.00V per cell. A pack with 3 cells in series (3S) has a voltage 3 times 3.00V or 9.00V for the 3S example pack.
   Even though the pack’s actual ‘capacity’, stated as a constant load current per hour, to go from ‘full V’ to ’empty V’, varies with the constant load current, the value is treated as a constant.
   The manufacturer is saying that when a constant load of 2100 milliamps (mA) is placed on this pack for 1 hour the voltage drops from ‘full V’ to ’empty V’.
   It is somewhat difficult for us to ‘think’ in milliamps.
   A milliamp (mA) is one thousandth of an amp.
   To ‘think’ in amps, divide milliamps (mA) by 1000.
   2100milliamps (mA) / 1000 = 2.1 amps (A)
   When amps (A) are used as the unit, the previous statement is easier to comprehend.
   The manufacturer is saying that when a constant load of 2.1 amps (A) is placed on this pack for 1 hour the voltage drops from ‘full V’ to ’empty V’.
   Capacity is measured by the manufacturer to a certain standard.

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Weedwackers Estate Sale & Auction – Plus Food!

Set the date – March 3rd!  at the Weedwacker’s Field.

Weedwackers will hold an estate sale/auction event to include a fine carne / pollo asada taco lunch. Some fun-fly events as well!

Sales will start at 10am with the Silent Auction items closing at 10:30.

Proceeds go to the respective families or estate.
Fun-Fly events will run from 9am until 10am (roughly).
Lunch will be served somewhere between 10 and 10:30. They’ll be collecting $5 per plate to offset the food cost.



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